Earth-working machines, for example, excavators, continuous miners, and loaders, often include tracked undercarriages that facilitate movement of the machines over ground surfaces. Such track-type machines typically include track assemblies located on either side of the machine. Each track assembly includes a chain having spaced apart pairs of links pinned end-to-end forming a loop that extends around a drive sprocket at one end of the chain and an idler wheel located at the other end of the chain. Some machines may include additional idler wheels or rollers to guide the links from the sprocket end to the idler wheel end. The track link assemblies often also include ground engaging track shoes connected to adjacent pairs of links. An engine associated with the machine typically drives the sprocket. Teeth on the sprocket engage with the links to rotate the chain, pushing the track shoes against a work surface and allowing the machine to be propelled in a forward or rearward direction.
The track links support the weight of the machine. In particular, the weight of the machine is reacted onto the pins connecting the spaced apart links of the track link assembly when the pins pass over an idler wheel or roller. The width of each link is reduced near the location of the pin so that adjacent links may overlap and be connected to each other through the pin. Because of the reduced thickness of the links, reaction of the machine weight on the pins induces high stresses in the links near the pin location. The links and pins may be exposed to these high stresses every time the links and pins pass over an idler wheel or roller. Repeated exposure to these high stresses may cause significant wear and/or breakage of the links. Repair or replacement of the worn or broken links may require expensive and labor intensive service operations, which can place the machine out of service for a long time. Thus, minimizing wear and breakage of the track links becomes important to prevent premature failure of the chains.
U.S. Pat. No. 7,530,650 B2 to Hannan et al. (“the '650 patent”) that issued on May 12, 2009 discloses a crawler shoe that attempts to distribute the load from a roller on the shoe uniformly as the roller travels from one shoe to an adjacent shoe. In particular, the '650 patent discloses a shoe for a crawler track. The disclosed shoe has two roller paths to allow a dual rim roller to travel on the track. The '650 patent discloses that the crawler shoe has a body having a leading lug and a trailing lug disposed on either side of the body. The '650 patent also discloses that the leading and trailing lugs are spaced laterally in a direction transverse to the direction of travel to allow adjacent shoes to connect with each other via a pin. Further, the '650 patent discloses that the crawler shoe includes a pair of spaced apart driving lugs that are engaged by teeth on opposite sides of a double sprocket to transfer motive power from the sprocket to the track. The '650 patent discloses that the offset leading and trailing lugs help to transfer the load of the machine more uniformly between adjacent crawler shoes as a roller travels from one shoe to the next.
Although the '650 patent discloses the use of a shoe with offset lugs to distribute load more uniformly, the disclosed shoe may still not be optimal. In particular, the disclosed shoe includes a dual drive lug feature, which may not be useable in track link assemblies in which the sprocket teeth engage with the pins connecting adjacent pairs of links to drive the track. Further, the shoe of the '650 patent requires two separate sprocket wheels to engage with the two separate drive lugs on each shoe. Adding two sprocket wheels to drive each track assembly may increase the cost of manufacturing and maintaining the undercarriage assembly. Moreover, replacing single sprocket wheels on existing machines with two sprocket wheels to drive each track assembly may make it cost prohibitive to implement the disclosed shoe on machines having a single sprocket wheel.
The undercarriage track link assembly of the present disclosure solves one or more of the problems set forth above and/or other problems in the art.